American College of Emergency Physicians
Fact Sheets

Lightning Injury

Main Points

  • Lightning is one of the most dangerous and frequently encountered weather hazards. It has been the second largest killer of people in storms in the United States since 1959.

  • The National Weather Service estimates that lightning strikes the earth about 25 million times per year in the United States.

  • A few simple precautions can reduce a person's risk for lightning injury.

    • Seek shelter when a thunderstorm is approaching.

    • Avoid tall structures, such as isolated trees and flag poles.

    • Stay away from open fields, open structure or vehicles, or contact with conducive material, such as computers and telephones.

    • Avoid being near or in water.

  • If you or someone you know is struck by lightning, seek medical care immediately. Someone struck by lightning does not carry a charge and is safe to touch.

  • Annals of Emergency Medicine published lightning safety guidelines in June 2002.

Q. What is lightning?
A.

Lightning is a flow of electrical current originating 15,000 to 25,000 feet above sea level. When particles in a cloud become charged and separate into positive and negative charges, it causes an electrical discharge. The current will sometimes discharge to the ground resulting in large voltage strikes. When lightning heats the atmosphere, it compresses the air and produces a shock wave, which generates sound or thunder. Light travels faster than sound; therefore, lightning is seen before it is heard.

Q. How likely is a person to be struck by lightning?
A.

Lightning is one of the most dangerous and frequently encountered weather hazards. It is second only to floods as the greatest cause of death annually by a natural hazard in the United States. A person's risk for lightning injury is most consistently related to their failure to take appropriate precautions.

Q. How can lightning injuries be prevented?
A.

If you plan to be outdoors, check the local weather forecast, and keep an eye on the weather. Plan ahead and avoid outdoor activities during a thunderstorm. Generally, if you can hear thunder, you are at risk, even if you don't see lightning. Don't wait until it begins to rain to find shelter, because lightning often precedes rain. The "30-30 Rule" is often used to calculate how far away a storm is from you. When you see lightning, count the number of seconds until you hear thunder. If the time delay between seeing the flash and hearing the bang is less than 30 seconds, seek shelter.

If you are outside before or during a lightning storm, locate shelter as soon as possible. An insulated building with plumbing and wiring is the best choice. A fully enclosed metal vehicle (windows up) is a choice if the only other alternative is to be openly exposed, but avoid touching metal outside or inside the vehicle.

If you are inside:

  • Turn off and stay away from electrical appliances, fireplaces, televisions, computers, and power tools.

  • Do not use the telephone.

  • Stay away from water.

  • Avoid metal objects.

  • Wait 30 minutes from last observed lightning flash before resuming activities.

Large groups should have lightning action plans that include an evacuation route, designated safe areas, and a warning signal. Someone should be assigned to monitor up-to-date weather information. Group members should know the difference between warning signals and all-clear signals. They also should be advised about what to do in the event of a storm.

Q. What are the effects of being struck by lightning?
A.

The effects of lightning strikes range from minor to life threatening. According to the guidelines published in Annals of Emergency Medicine, 90 percent of people struck by lightning survive, but they may suffer permanent after-effects and disabilities. Lightning may not leave significant evidence of external injury, but internal injury can sometimes be extensive. Strikes can result in: impaired eyesight, ear ringing, ruptured ear drums, or loss of hearing; loss of consciousness; severe electrical shock; seizures, paralysis, external burns to the skin; internal burns to organs and tissues; blunt trauma (from falls); and cardiac arrest. Long-term effects can include cataracts (should be checked 6 months after incident), sleep disturbances, memory dysfunction, headaches, irritability, fatigue, abnormal gait, joint stiffness, muscle spasms, and dry eyes.

Q. What can you do for a person who has been struck by lightning?
A.

Seek immediate medical attention. A person struck by lightning may be unconscious, disoriented, or unable to speak. The victim also may have stopped breathing. If he or she is not breathing, begin rescue breathing, once every 5 seconds for adults and once every 3 seconds for infants and small children, until medical help arrives. If the victim does not have a pulse, and you know CPR, begin external cardiac compression. If he or she is bleeding or burned, apply appropriate first aid. Victims will not retain an electrical charge, so it is safe to touch them.

Q. What is the medical treatment for someone who has been struck by lightning?
A.

Any person struck by lightning is observed for several hours from the time of the strike. A panel of laboratory testing is performed to establish evidence of electrolyte abnormality or extensive muscle breakdown. Cardiac monitoring also may be performed. In the event the victim fell or was thrown, X-rays may be necessary. If any abnormalities are evident, the victim may be admitted to the hospital for further diagnostic work-up and treatment.

American College of Emergency Physicians: June 2003